Lightning-arrester



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N0.'414,356.' Patented Nov. 5, 1889.

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(No Model.) 2 Sheets-Sheet 2. G. WIRT. LIGHTNING AERESTER.

No. 414,356. Patented Nov. 5, 1889.

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CHARLES IRT, OF ORANGE, NEN JERSEY.

LIGHTNING -ARRESTER.

SPECIFICATION forming part of Letters Patent No. 414,356, dated November5, 1889.

Application filed August 15, 1889. Serial No. 320,810. (No model.)

To all whom it may concern:

Be it known that 1, CHARLES WIR'T, a citizen of the United States,residing at Orange, in the county of Essex and State of New J erment inLightuing-Arrestcrs, of which the- .lhe general object of my inventionis to protect from lightning-electrical systems in which currents ofcomparatively high tension are employed, such as systems of electriclighting and electric-railway systems. In such systems difiiculty oftenarises in the use of ordinary lightning-arresters--such as those usingtoothed plates-because the passage of the lightning discharge to earthacross the break forms an arc, across which the current I of the systemwiil pass to earth and continue to do so unless the arc is broken insome way. Various electrical and mechanical devices have been proposedand used for this purpose; but allot these have been foundunsatisfactory in one way or another.

It is my especial object to avoid the difficulty above mentioned in asimple and effective way, and I accomplish this by providing the novelform of lightning'arrester hereinafter described, which is of suchcharacter that, while the lightning discharge can pass freely through oracross it to earth, no arc can follow it.

My lightning-arrester consists, generally, of amultiplicity of metalplates not in any way electrically connected with one another andmassed'clos e1 y togeth er, with only exceedingly slightinsulating-spaces between them. One end of the series of plates isconnected .with the exposed circuit and the other end to earth. Theinsulation between the plates is preferably formed by thin plates ofmica; but an air-space may be employed instead. I have found that withsuch an arrangement the lightning discharge will pass readilyacross thewhole series of plates, traveling when insulation is placed between theplates either along their edges or through apertures which I sometimesform in the insulation; but no arc will follow the discharge because ofthe great number of points at which the circuit is broken.

With the ordinary toothed lightning-arrester the lightning dischargeheats the air to vapor are not raised to the high temperature requiredto form the continuous conducting pat-h necessary to convey thefollowing current.

My invention is capable of various forms, some of which are illustratedin the annexed drawings.

Figure 1 is atop view illustrating a form of myinvention employingrectangular plates with insulation between them; Fig. 2, a top View, andFig. 3 aside view, of a form in which the edges of the plates areseparated by airspace; Fig. 4., a side elevation of a form employingcircular plates of metal and mica. Figs. 5 and 6, respectively, areviews of the metal and mica plates of Fig. 4:; and Fig. 7 is a diagramshowing my invention applied to a system of electrical distribution.

Referring first to Fig. 1, the series of rectangular metal plates CL 0,are clamped closely together with thin sheets of mica bb between them.The plates are placed between the cross-pieces c, of suitable insulatingmaterial, and are drawn tightly together by means of bolts (Z and nutse. 011 each insulatingpiece 0 is a plate f and binding-post g, at whichthe circuit-wires, leading one to earth and the other to the circuitwhich is exposed to lightning, are attached. Thin strips h at each endconnect the binding-post with the .end plate of the series, beingclamped beneath the plate f and between tl'ieinsulatingpiece 0 and theoutermost plate a. Afusible safety-catch 7:- may be inserted at one endas an additional means of safety, if desired. In this form of myinvention the lightning discharge passes freely to earth along the edgesof the metal plates; but the formation of a following are is preventedby the multiplicity of plates and breaks. Each break is of such slightwidth that the whole amount of insu lating space is no greater than thesingle space of the ordinary lightning-arrester, and

the lightning discharge is readily conveyed across the whole series; butthe division of the space into so many parts prevents by the cooling ofthe vapor, asalready explained, the formation of the following arc. Fig.1 shows the lightning-arrester of the size used by me in practice andwith a sufficient number of plates and intermediate spaces for use witha current of about one thousand volts. The number of plates may to someextent be increased or diminished, according to the character of thesystem to be protected and the varying conditions which may arise inpracrice, the number being always small enough to let the lightningdischarge pass freely and large enough to give the necessarycoolingspace for the arc. I find that the best proportion is aboutthirty plates for each one thousand volts of the current.

' In the form shown in Figs. 2 and 3 a suitable number of metal platesZlare fixed upon a'strip m of insulating material, with their edgesclose together, but not touching. The end plates are connected incircuit, as above described, and the operation is the same as alreadyset forth. The discharge passes freely across the air-spaces between theplates, but the following arc is prevented by the multiplicity ofbreaks.

' In Fig. 4a series of circular metal plates n n are clamped betweendisks 0 0, attached to a suitable base A, and have placed between themthin perforated mica plates 19, Fig. 6. The metal plates n n and o 0have each, Fig. 5, a centralhub q, of insulating material, and a bolt w"is passed through them, so that the Whole is drawn tightly together by anut r, the nutand bolt-head being insulated from plates '00 byinsulating-washers s s. The

mica plates are larger than the metal ones and their edges extend beyondthose of the metal plates, so that the discharge does not pass along theedges; but the perforations t t in'the mica plates furnish a passage forthe lightning between the metal plates, which the current of the systemdoes not follow, for the reason already explained. I

In Fig. 7, u represents a generator supplyin g translating devices 12 oof a system of electrical distribution. Lightning-arresters embodying myinvention are indicated at w to, they being connected between the mainconductors of the system and the earth and protecting the generator andtranslating devices from atmospheric discharges, as above de scribed.

\Vhat I claim is 1. A lightning-arrester consisting of a multiplicity ofelectrically-unconnected metal plates separated by slightinsulating-spaces, substantially as set forth.

2. A lightning-arrester consisting of a multiplicity ofelectricallyunconnected metal plates with thin plates of insulatingmaterial between them, substantially as set forth.

3. A lightning-arrester consisting of a mul tiplicity ofelectrically-unconnected metal plates, thin plates of insulatingmaterial between them, and clamping devices for holding the wholeclosely together, substantially as set forth.

4. A lightning-arrester consisting of a multiplicity ofelectrically-unconnected 'metal plates with thin perforated plates ofinsulating material between them, substantially as set forth.

5. A lightning-arrester consisting of alternate plates of metal andinsulating material, a bolt passing through said plates, a clamping-nuton said bolt, and insulating material interposed between said bolt andnut and the metal plates, substantially as set forth.

This specification'signed and witnessed this 12th day of August, 1889.

' CHARLES XVIRT.

Vitnessos:

WILLIAM PELZER, D. H. DRISCOLL.

